Date of Award


Degree Type


Degree Name

Honors Thesis



First Advisor

Joel Martin


Research shows that there may be a connection between substance use and the expression of positive psychosis symptoms, most notably delusions and hallucinations (Stefanis, et al. 2004). While substances such as marijuana have received the most attention in the literature (e.g., Grech et aI.., 2005), other substances such as stimulants (e.g., Curran et aI., 2004), tobacco (e.g., Baeza et aI., 2009), and alcohol (e.g., Compton et aI., 2009) have been implicated in exacerbating the risk of psychosis onset. Further, there is mounting evidence that many psychiatric disorders are not discrete categories but rather the tails of dimensions distributed in the general population (e.g., van Os & Linscott, 2012). Often referred to as "delusion proneness" and "hallucination proneness," subclinical levels of delusional ideation and hallucinatory experiences (respectively) have emerged as useful ways to understand more about how individuals with psychosis understand their world. The present study further explored the relationship between adolescent substance use and psychotic symptoms of delusions and hallucinations. Data were collected from 248 students enrolled in a number of Midwestern universities. Participants responded to questions about past and present usage of alcohol, tobacco, marijuana, cocaine, opioids, stimulants and hallucinogens and also completed measures of delusional ideation and hallucinatory experiences. Results suggest that alcohol use may serve a suppressing function for delusional and hallucinatory symptoms, but only in certain circumstances. Results also suggest that early use (defined as age 14 or earlier) of either marijuana or alcohol may increase delusional ideation.